It's the time of year where we all give thanks, and among many other things, we here at Lifehacker are thankful for all the free apps out there that improve our lives (and the developers that make them!). Here are 50 of our favorites.

Adblock Plus is one of the most robust browser extensions out there, and while its namesake is its most-used feature, it's not just about blocking ads. In fact, you can do all sorts of things with it, including cleaning up Facebook's interface and making sure web sites aren't tracking you.

Web: 100 wants to motivate you into learning a new skill in a hundred days by tracking your progress each day through a short video post. Along the way, people can like your vids and send you a few words of encouragement too.

If you thought that hitting "Update All" on the Play Store meant you have the most recent version of an Android app, you'd be wrong. There are plenty of ways to get faster rollouts or even experimental builds for the adventurous.

iOS/Android: While there are lots of things you can do to find the cheapest airfare, why not let technology make the effort while you sit back? Hitlist finds out when it's least expensive for you to grab a flight to your pre-picked destinations, saving you the hassle of periodically checking travel search engines.

Chrome/Safari: Streak, an email organization suite for Gmail, unveiled message tracking today. Now, it integrates with Gmail (or Google Apps), pops up a message to let you know when a message has been read, and offers a timeline view so you can see who's read it, when, and on what devices. Best of all, it's free.

Android: If you suspect your roommate or anyone else has been reading your private messages on your phone, then PeeperPeeper can catch them red-handed. The app creates fake shortcuts for popular messaging apps and takes a photo when someone opens them.

iPhone: Sometimes, creating a schedule for your day is less about a series of things on a calendar and more about a list of projects you want to make. TIME Planner is an app that makes it pretty easy to create a colorful and easy to read schedule for your day in a matter of seconds.

Android: One of the neatest things about the Chromecast is the ability to launch videos on your phone and then stream them to your TV. If you don't want to use the Chromecast, though, AllCast allows you to stream local videos from your Android device to any DLNA-compatible player.